The Magazine for Specialist Printers

A whiter shade of pale

Originally published in Issue 3 / 2017 of Specialist Printing Worldwide, Gabriele Heller discusses the consequences of the RAC’s recently published recommendation on the classification of titanium dioxide

In November 2015, the French Anses – Agence nationale de sécurité sanitaire, de l’alimentation, de l’environnement et du travail – provided the European Chemicals Agency (ECHA) with a proposal for a harmonised classification of titanium dioxide as an inhalative carcinogen (Carc. 1B – H350i).

Titanium dioxide is the white pigment used in manufacturing white ink shades, but also in high opaque coloured shades. Due to the high opacity and the high degree of whiteness, there is no alternative white pigment available with similar technical properties.

On 8 June 2017, the Committee for Risk Assessment (RAC) of the European Chemicals Agency ECHA published its recommendation on the subject. It suggests a harmonised classification of titanium dioxide as Carcinogen, Category 2 (‘suspected human carcinogen’), thus opposing the French proposal.

DefenceThe industry, however, considers any classification of titanium dioxide as carcinogen to be neither justified nor appropriate, for the following reasons:

When establishing the REACH registration dossier back in 2010, comprehensive evaluation of all available scientific data had been carried out, leading to the conclusion that titanium dioxide doesn’t need to be classified as hazardous according to the criteria of the CLP regulation.

The French proposal is based on a so-called ‘lung overload study’ in rats. It is a known fact that exposing rats to high amounts of any kind of dusty materials causes tumours to grow in the lungs of the testing animals. Humans, however, don’t react this way when exposed to inert dust.

In most of the EU member states occupational workplace exposure limits for dust have been established.

Epidemiological studies performed over several decades in about 24,000 workers at 18 production sites also showed no negative effects on the health caused by exposure to titanium dioxide.

Although the supposed carcinogenic properties of the product are related to dust inhalation, a classification as Carc. Cat, 2 will result in the same classification of all products containing TiO₂ in amounts exceeding 1%. This is also the case for liquid and paste products like printing inks, despite the fact that from such products no dust inhalation of the TiO₂ contained can occur. This problem results from the hazard-based classification requirements of CLP regulation not taking into account whether there is indeed a risk. As, however, no dust inhalation is possible from liquid and paste products, labelling of this kind of products as Carc. Cat. 2 doesn’t make sense and is misleading the customers.

Titanium dioxide is a so-called ‘inert dust’. As rats respond with tumour building when exposed to any kind of inert dust, it can be expected that other dusty materials, although chemically inert, will be classified the same way in the future.

Other consequencesAlthough a Carc. Cat. 2 classification, as opposed to a Carc. Cat. 1B, is not considered to be a substance of very high concern (SVHC) and thus will not appear on the candidate list and finally on Annex XIV of REACH regulation (‘Authorisation List’), there are still other consequences to be considered:

Legal requirements resulting from this classification (labelling, documentation, plan engineering…) will have to be complied with by EU manufacturers of titanium dioxide and mixtures containing the substance, thus leading to competitive disadvantages compared to producers outside of the EU.

Printing on ‘sensitive’ products like toys or food contact material will no longer be possible with inks containing titanium dioxide, as the use of carcinogenic substances in manufacturing such products is not allowed – no matter of which category the substance is classified.

Customers trying to achieve a ‘green’ image usually exclude the use of ‘critical’ substances in products delivered to them. Thus it is to be expected that such customers will put pressure on their suppliers to substitute titanium dioxide in the products delivered to them. Substitution, however, in many cases will not be possible as there is no other white pigment available providing similar technical properties (opacity, whiteness, brightness…). Now it is up to the EU commission to decide whether it considers the proposal to be appropriate.